we should realize the MarkJoin as HashJoin

zhouqingqing / qpmodel

A Relational Optimizer and Executor

MIT License

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Open 9DemonFox opened 3 years ago

9DemonFox commented 3 years ago

When a markjoin deprived from IN clause, it can't be seen as a semi join, because there might be a "null".

9DemonFox commented 3 years ago

More precisely, EXIST, IN should use SEMI JOIN， but NOT IN is not SEMI JOIN. Understanding this , the work to simplefy markjoin can work on.